United Kingdom Published Patent Application No. 22 93 681, describes a conventional upfront sensor for determining plausibility for the triggering decision of the central control unit for restraint systems.
International Published Patent Application No. WO 97/48582 describes a system for sensing a head on collision. In this context, an impact sensor is accommodated in a control device, and an additional collision sensor is located in the vehicle front as an upfront sensor. This upfront sensor is used as plausibility sensor for the impact sensor in the control device. From German Published Patent Application No. 42 02 460, a system may be gathered in which an acceleration signal is linked in an OR-operation to a speed signal of an acceleration sensor. In German Published Patent Application No. 197 40 019 it is described to buffer-store a plausibility signal for a predefined time.